Many piping systems utilize plastic or polyvinylchloride (“PVC”) pipe to transmit the system fluids from one location to another due to its relatively low cost and ease of installation. The use of such materials is particularly prevalent in the low pressure water piping systems utilized in irrigation or sprinkler systems for home and business locations. Typically, lengths of pipes are joined without threading by utilizing standard couplings that attach to the end of a section of pipe with a solvent cement or like adhesive and the piping system is buried beneath the ground. The standard piping system coupling comprises a small section of pipe having opposite facing open ends with inner diameters sufficient for the ends of the pipes to be joined to fit snugly within the coupling. The ends of the pipes typically abut against a small inner disposed wall that prevents the pipe from extending through the coupling. To secure the pipe to the coupling, a quantity of solvent cement is applied to the outer surface of the pipe at its end and/or to the inner diameter of one side of the coupling before the end of the pipe is inserted into the coupling. Although a seal between the pipe and coupling can be obtained by merely inserting the pipe linearly into the coupling, it is well known that even a very small piece of plastic, rock, dirt or other debris can result in a longitudinally disposed channel that will create a path for a leak. As a result, the generally recommended procedure for joining the pipe to the coupling is to push the end of the pipe into the coupling and then manually twist the pipe and/or coupling relative to the other so as to wipe the adhesive around the outside of the pipe and inside of the coupling and disrupt or eliminate channels by capturing and surrounding any debris left on the end of the pipe.
Unfortunately, underground plastic or PVC pipes are known to be relatively easily damaged due to contact with a shovel, hoe or other implement or to otherwise split or break causing the fluids therein to leak out. As well known in the art and described in U.S. Pat. No. 6,692,035 to Baruh and U.S. Pat. No. 4,687,232 to Zimmerman, to repair a section of broken pipe that is located underground it is first necessary to isolate the broken section by excavating an area around the break and then cut the pipe to remove the section of damaged pipe, thereby leaving the pipe with two facing, generally aligned ends. The conventional manner of repairing the pipe is to insert a section of pipe of sufficient length to fit within the removed section. To join to the ends of the cut pipe, the repair pipe will have a standard pipe coupling at each end that is sized and configured to receive the ends of the pipe where the section was removed. Joining the coupling at one end of the repair pipe to one end of the cut pipe can generally be done in the same push and twist manner used for installing new pipe since it is possible to twist the coupling relative to the fixed cut pipe. Joining the coupling at the second end of the repair pipe to the opposite end of the cut pipe is generally much more difficult. Typically, the desired twist motion to obtain a seal cannot be achieved because the coupling at the first end of the repair pipe is now joined to the first end of the fixed, buried cut pipe. In addition, because the repair pipe is sized to fit within the cut area, the second end of the cut pipe and the corresponding end of the repair pipe must be bent at an angle in order for the end of the cut pipe to go inside the coupling. In order to have sufficient freedom of movement to achieve the necessary angle, the person repairing the pipe must excavate a much larger area around the broken pipe than would otherwise be necessary to just fit in the repair pipe. If the excavated area is large enough and two or more people are available, an insert and twist motion can be achieved at both ends of the repair pipe by placing adhesive at both free ends of the cut pipe or in both couplings, sufficiently bending both of the pipe ends to direct them into the couplings at the opposite ends of the repair pipe at the same time and then twisting the repair pipe, so as to twist both couplings, before the adhesive has a chance to set.
As set forth above, the conventional method of repairing a section of damaged underground pipe is somewhat difficult and, if paying someone to perform the work, expensive to accomplish. In addition to the time and cost of digging an enlarged excavated area, the digging carries an inherent risk of making contact with the piping system elsewhere and causing a second break. Bending the pipe a sufficient amount to be able to insert the end of the pipe into the repair coupling can result in a split or break in the pipe, particularly if the pipe is older and, therefore, more likely to be relatively brittle. The problems with bending the buried pipe are somewhat exasperated when dealing with larger diameter pipes, as these are more difficult to bend, and pipes which are buried deeper below the surface of the ground. Another problem with the conventional manner of repairing damaged, buried plastic or PVC pipe is that the repair person must ensure that the repair pipe, with couplings at both its ends, is of the proper length. If the repair pipe is too long, then it will not fit into the cut section space or, if forced to fit, it will place significant stress on the piping system. If the repair pipe is too short, then it will not join to both ends or, even if it does join both ends, it will not have sufficient joining area to provide the desired seal. In addition to the above, the inability to twist both ends of the coupling and/or cut pipe creates the potential for debris-formed channels that will result in a leak.
To address the problems associated with the conventional manner of repairing a damaged section of buried pipe or the like, a variety of different repair couplings or systems have been developed, a number of which have been patented. One type of pipe repair system comprises one or more clamping mechanisms which fit over the pipe to engage the pipe and seal against the break. Another type of pipe repair system utilizes a pair of clamping mechanisms that connect to the opposing free ends of a cut pipe so as to span a repair pipe across the cut section of pipe. Yet another type of pipe repair system comprises a collapsible repair coupling that fits within the cut section of pipe and then extends to connect the two generally aligned, spaced apart ends of the pipe. Examples of patents directed to this latter type of pipe repair system includes U.S. Pat. No. 4,687,232 to Zimmerman, which describes a pipe slip joint system having an expandable pipe coupling comprising a joint housing that encloses a tubular piston which protrudes from one end of the housing. The piston is compressed and inserted into a small cutaway section of an existing pipe and then expanded to fit over the two free ends of pipe to form a continuous water-tight connection. Another such patent is U.S. Pat. No. 4,013,309 to Quick, which describes a repair kit for plastic pipe having two or three tubular components, one of which is a coupling sleeve, that are configured for telescopic assembly to the adjacent ends of a broken pipe. The coupling sleeve spans the break so that its end portions can be adhesively bonded to the exterior of the ends of the broken pipe. Yet anther example of an extending type of device is U.S. Pat. No. 4,386,796 to Lyall, et al., which discloses a pipe repair coupling comprising a barrel that telescopically receives a hollow piston, formed with a plurality of annular O-ring grooves that each have an O-ring which seals against the interior wall of the barrel. One end of the barrel has a coupling that engages one end of the cut pipe. The piston is telescoped into the barrel such that its outwardly extending, free end may be connected to a standard coupling that engages the other end of the cut pipe. A different type of device is set forth in U.S. Pat. No. 6,692,035 to Baruh, which discloses a pipe coupling device that comprises an elongated housing defining an elongated bore therein that has a stop disposed between the first and second ends of the housing. The stop is located approximately twice the distance from one end of the housing than it is from the other end. In use, the user applies adhesive to the inside surfaces of the coupling, inserts the longer end of the housing onto one end of the cut pipe, bends that end of the pipe out of alignment with the opposite end of the cut pipe and then slides the other end of the housing over the free end of the cut pipe.
Although the foregoing devices can be utilized to join two opposing, spaced apart ends of a cut section of pipe, none of these devices or any other device known to the present inventor or assignee provides a pipe repair coupling that is configured to allow the user to engage and twist both ends of the coupling relative to the cut pipe so as to eliminate channels in the adhesive which can result in a leak. What is needed, therefore, is a repair coupling for joining two ends of a cut section of pipe that can be placed between the two ends so as to join the pipe ends and allow the coupling to be twisted relative to both ends of the pipe to wipe the adhesive around the inside surface of the coupling and the outside surface of the ends of the pipe to prevent channels that can result in a leak. The preferred pipe repair coupling should include a mechanism that allows the user to push and twist one end of the coupling onto a first pipe end and, with the coupling extended between the pipe ends, then push and twist the coupling onto the second pipe end to sealably engage both ends of the pipe. The preferred pipe repair coupling should also be configured to be easily and quickly installed between the ends of a cut section of pipe to connect the pipe ends without having to bend the pipe to be repaired. Preferably, the pipe repair coupling of the present invention should be configured to provide a sealed contiguous channel between two ends of a cut section of pipe. The preferred pipe repair coupling should also be adaptable to a wide range of pipe sizes and configurations.